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Jim Fier, Vice President Engineering – Engine Business at Cummins.

Raising the bar on engine performance at emissions changes

The next level of off-highway emissions regulations to impact the industry is the European Union’s (EU) Stage V standards, planned to take effect in January 2019. While Stage V will not be applicable in North America, product improvements made to meet the regulations are expected to be made available for the North American market. Additionally, North American equipment manufacturers selling equipment into Europe will need to use Stage V engines beginning in 2019.

The new rules are challenging engine manufacturers to meet more restrictive levels of emissions. Alongside the ultra-low particulate matter (PM) and oxides of nitrogen (NOx) limits of the U.S. EPA Tier 4 Final standards, Stage V includes a particulate number (PN) count measurement rather than weight. The maximum amount of particulates emitted for each kW of engine output per hour is set at 10¹²/kW·h. This will mandate the use of a diesel particulate filter (DPF) on all installations from 25 to 750 hp (19 to 560 kW) and drive real-world PM emissions to virtually zero, while supporting the EU’s focus on air quality improvements.

In designing ultra-clean engines to meet Stage V regulations, Cummins maintained a focus on customer needs, as well as the need to meet more stringent regulations. This customer-inspired design resulted in simpler exhaust gas recirculation (EGR) -free architecture and Single Module aftertreatment, resulting in significant increases in power and torque as well as reduced cost of ownership. Cummins’ midrange engines for Stage V, the F3.8, B4.5, B6.7, and L9, spanning 100 to 430 hp (75 to 321 kW), will deliver greater than 10% more power and 20% more torque, on average, than their Stage IV/Tier 4 Final equivalents.

Increases in power and performance

Cummins 4- and 6-cylinder engines make significant power leaps at Stage V. The F3.8 moves from 130 hp (97 kW) at Stage IV up to 155 hp (116 kW) at Stage V, while the B4.5 jumps from 173 hp (129 kW) to 200 hp (149 kW). Coupled with peak torque increases of more than 20% (to 600 N·m) for the 3.8 and 11% (to 780 N·m) for the 4.5, the 4-cylinder engines enable significant opportunities for OEMs to downsize installations without sacrificing power or performance.

Similarly, the best-in-class Cummins B6.7 and L9 6-cylinder engines also gain power and torque. The rated power for the 6.7-L increases to 326 hp (243 kW) with peak torque of 1375 N·m (lb·ft), a 30% increase over Stage IV. The L9 picks up 30 hp (22 kW) to top out at 430 hp (321 kW) at Stage V and gains a 13% increase in peak torque to 1846 N·m (1362 lb·ft). With gains like these the B6.7 and L9 will remain performance leaders for all types of medium- and heavy-duty equipment.

These substantial gains in power and performance are applied across the full engine speed rpm range, making the Stage V engines more adaptable to different machine-load demands. Availability of either high power at high engine rpm or high torque at low engine speed rpm combined with smart electronic feature sets and calibration shaping ensures that every application receives the ideal performance curve for the operation of the machine.

Designed for simplicity

Cummins’ Stage V product lineup also offers OEMs and operators a very simple operating solution. Removing EGR unleashed the full potential of each engine at Stage V without increasing displacement, which means there is less to cool making OEM integration simpler while keeping costs low.

The use of a single Cummins turbocharger on the full Stage V engine range also reflects simplicity and customer benefits. The latest high-efficiency wastegate turbocharging is used on the F3.8, B4.5, and L9 engines. Proven variable-geometry technology remains in use on the B6.7, with the Holset VGT achieving exceptional power density with fuel-efficient performance.

Aftertreatment technology also benefits from simplicity at Stage V. The Cummins Single Module combines DPF, SCR (selective catalytic reduction), and urea-dosing technologies in one module, providing an up to 50% reduction in envelope size and a 30% reduction in weight compared to Stage IV exhaust aftertreatment. Essentially a fit-and-forget system, the Single Module is capable of removing emissions almost entirely by passive regeneration with no impact on equipment operation and without intervention from the operator. Operators will also enjoy simplified maintenance, with an achievable 1000-hour oil change interval that is double the current 500 hours. These changes ease installation for OEMs and deliver tangible benefits to operators.

Electronics enhancements

Cummins Stage V engines are equipped with Start-Stop technology embedded in the engine management system. This technology offers the potential to realize fuel savings between 5% and 15% based on the amount of equipment idle time. The engines are also enabled for wireless connectivity, enabling them to deliver instant, expert engine diagnostics over-the-air, which allows operators to maximize the uptime availability of their equipment.

Global products

The products introduced to meet Stage V regulations in 2019 have been designed with a high tolerance to sulfur in fuel—up to 5000 parts per million—removing a barrier to reaching the goal of a universal engine design. This high tolerance level offers OEMs the opportunity to use the same Cummins Stage V engine in their equipment worldwide, delivering a common engine installation with the same electronic integration and mechanical hookups with or without aftertreatment depending on emissions levels.

The engines will also be co-certified to meet U.S. EPA Tier 4 Final regulations as well as equivalent emissions regulations in Japan and South Korea, reducing the complexity OEMs face when powering their global equipment platforms.

Cummins’ commitment to going beyond simply meeting increasingly stringent emissions regulations has resulted in Stage V technologies that deliver higher power and torque, with more simple aftertreatment, on products that can be used globally. This kind of innovation results in products that meet the demands of both customers and regulatory agencies.

Jim Fier, Vice President Engineering – Engine Business at Cummins, wrote this article for Off-Highway Engineering as part of the annual Executive Viewpoints series appearing in the June 2016 issue.

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